The Internet is growing very fast, so finding the right information among billions of Web pages and millions of files day by day is becoming more and more difficult. There are many different kind of search systems which updated information about the location of Web pages and files for solving this problem.
What is a search engine?
Search engine - a tool for searching information on the Internet.
Search engines contain thematically grouped information about resources of the World Wide Web in databases. Special robot programs periodically read all the documents in the World Wide Web, highlight the keywords in them and enter the Internet addresses into the database.
Most search engines allow the author of the Web site to enter information into the database by filling out the registration form. In the process of filling in the questionnaire, the developer of the site introduces the site address, its name, a brief description of the content of the site, as well as keywords on which it will be easier to find the site.
How to use?
Search by keywords. Search for a document in the database of the search system is carried out by entering queries into the search field.
The request must contain one or more keywords that are primary for this document.
After the request the search engine makes the list of Internet addresses where the specified keywords were found. To view this document in the browser, it's enough to activate the link pointing to it.
In case when keywords were chosen unsuccessfully, the Web-link list will be too large (it can contain tens or even hundreds of thousands links). In order to reduce the list, you can enter additional keywords in the search field or use the catalog of the search engine.
Variety of search engines.
There are different kinds of search engines. One of the most complete and powerful search engine is google, which stores 8 billion Web pages in its database and every month the robot programs bring into it 5 million new pages.
In RuNet (the Russian part of the Internet) there are also big databases. For example, such search engines as Yandex and Rambler.
Search in the hierarchical directory system.
In the search engine's database Web-sites are grouped into hierarchical thematic catalogs, which are analogues of the thematic catalog in the library.
The search for information in the catalog is reduced to selecting a specific directory. Then the user will have a list of the most visited and meaningful Web sites. Each link is usually annotated.